Tan Sri Dato' Seri Haji Osman Aroff was born in Kampung Klubi Jitra, Kedah on 23 November 1940. He received his early education in Jitra Malay School up to Standard four. In 1951, he went on to continue with his secondary school education in Sultan Abd. Hamid College, Alor Setar, Kedah. He passed his Senior Cambridge in 1958. From 1959 until 1963, he continued with his studies in Political Science in the University of America in Washington, U.S.A.

Because of the talent he had shown in leadership, he was appointed as the UMNO Secretary of Tanah Merah Branch in 1956. Two years later, he was responsible for the setting up of the Jitra UMNO Division after the dissolution of the North Kedah UMNO Division. He was appointed as the Division's first UMNO Youth Chief. However the Jitra UMNO Division was later converted to the present Kubang Pasu UMNO Division.

Tan Sri Dato' Seri Haji Osman Aroff moved up another step in the political ladder when he was chosen to stand in the General Elections of 1969. This turn of events forced him to resign his post as the Taiwanese Council's Information Officer; a job he had held since 1966.

Because of the record of sterling services he had so far rendered, he was appointed as a member of the Kedah State Executive Council. He was also entrusted to deputize as Menteri Besar, when Dato' Seri syed Nahar went on leave from December 1984 until January 1985. On January 24, 1985, Dato' Seri Syed Nahar announced his resignation as Menteri Besar and named him as his successor. Tan Sri Dato' Seri Osman bin Aroff took his oath of office as the sixth Menteri Besar of Kedah at the Audience Hall of the Anak Bukit Palace on 28 January 1985.

As Menteri Besar, he also became Kedah UMNO Chief Liaison Officer and Chairman of Kedah Barisan National. He then resigned from the post of Kubang Pasu UMNO Chief, a post he had held from 1969 till 1972. This was done to allow Dato' Seri Dr. Mahathir Mohamad to take over the post of chairman while he himself acted as his deputy, a position he had held up to the present. At the national level, he was appointed as a member of UMNO Supreme Council. Tan Seri Dato' Seri Osman bin Aroff retained his seat for the Jitra constituency of the State Legislative Assembly through the 1986, 1990 and 1995 General Elections.

Tan Sri Dato' Seri Osman Aroff mengangkat sumpah sebagai Menteri Besar Kedah yang keenam di Dewan Penghadapan Istana Anak Bukit pada 28 Januari 1985.

Tan Sri Dato' Seri Osman bin Aroff was very fond of using pragmatic and realistic approaches to his administration. He worked to turn Kedah into a developed state in as many sectors of possible, such as the industrial sector, the agricultural sector, the business sector, in education and tourism. In development, he stuck to UMNO's objective of progressing with the people and sharing with them, the wealth of the State. The challenge the State faced under his leadership was to transform from a State based on agriculture into an industrial one. To do this a plan, known as the Action Plan for the Development of the State (PTPN) was launched. Its long-term programme was a comprehensive one and was aimed at modernizing the economy and to increase productivity as well as Kedah' revenue. The plan gave priority to three main sectors; the industrial, the tourism and the commercial farms sectors. He also worked at improving the State's economy so that it would become stronger, and at the same time retained a balance between the State's economic and manpower resouces.

In recognition of his services to the State and Nation he was honoured with the Panglima Setia Mahkota (P.S.M) by the Yang Dipertuan Agong, which carries the title of Tan Sri, the Seri Setia Di Raja Kedah (S.S.D.K.), the Dato' Paduka Seri Sultan Abd. Halim Mu'azam Shah (D.H.M.S.), the Johan Mangku Negara (J.M.N.) and the Jaksa Pendamai (J.P.).